Yellow sulfur dye and process of making same.



UNITED STATES PATENT OFFICE.

ARTHUR WEINBERG AND OTTO LANGE, OF FRANKFORT-ON-THE-MAIN,

GERMANY, ASSIGNORS TO LEOPOLD OASSELLA & 00., OF FRANK-FORT-ON-THE-MAIN, GERMANY.

YELLOW SULFUR DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 712,747, dated November4, 1902.-

Applioation filed July 14) 1902. Eerial No. 115,685 (No specimens.)

ing is a specification.

We have discovered that if sulfur is allowed to act upon toluylenediaminat a temperature not exceeding 220 centigrade derivatives hithertounknown are formed, which by means .of a subsequent process may be madesoluble in water and in this form are exceedingly valuable, directdyeing yellow cotton dyestufis. The best proportions of toluylenediaminand sulfur are about one to two. The bases are, however, still obtainedWhen working with the proportion of one to 1.5. The

quantity of sulfur may be increased even to one to four, as the excessof sulfur remains unaffected.

The method of production is illustrated by the following example: Fiftykilos meta-toluylenediamin are introduced into one hundred kilos sulfurpreviously melted in an iron vessel provided with stirrers. The melt isrendered fluid on the temperature being raised, and sulfureted hydrogenis generated with violence. The temperature is then raised withintwohourstoabout190centigradeandthen the melt stopped. The sulfur body soobtained is a brown-yellow to orange-yellow amorphous substanceinsoluble inall organic solvents, water, dilute acids, or alkalies. Itdissolves a little.in concentrated sulfuric acid With a brownish color.For transforming this body into a soluble dyestuff it is preferablyheated with concentrated caustic-soda lye or a concentrated solution ofsodium sulfid. Water must, however, always be present in this operation, and the temperature should not exceed 150 centigrade.

The method of transformation is illustrated by the following example:One hundred kilos of the powdered melt obtained according to Example Iare gradually introduced at 110 centigrade into a solution of ninetykilos caus tic-soda lye dissolved in sixty kilos water and heated to 110to 120 centigrade until a test shows that the body has become completelysoluble. Water is then added fordilutingpurposes, the solution filteredoff, and the dis* solved dyestuff separated by the addition of muriaticacid. It is obtained as a difficultlysoluble yellow precipitate. It isthen filtered off and dried. The dyestuff so obtained is easily solublein water in the presence of caustic alkalies or alkaline sulfids anddyes unmordanted cotton yellow shades of absolute resistance to washing,milling, and acids. It is almost insoluble in concentrated sulfuricacid.

Having now described our invention and in what manner it may be carriedout, what we claim is- 1. The process of producing yellow sulfurdyestuffs by heating meta-'toluylenediamin and sulfur together at atemperature not exceeding 220.centigrade and converting thethus-obtained insoluble substance into asoluble dyestuff by heating itwith caustic alkalies or alkaline sulfids substantially as described.

2. The yellow coloring-matter containing sulfur obtainable ashereinbefore described, soluble in water in the presence of causticalkalies or alkaline sulfids with a yellow color, almost insoluble inconcentrated sulfuric acid, dyeing unmordanted cotton fast yellow shadessubstantially as described.

Signed at Frankfort-on-the-Main, in the Province of Hesse-Nassau,Kingdom of Prussia, Germany, this 18th day of June, A. D. 1902.

Witnesses:

JEAN GRUND, CARL GRUND.

